1. Minnesota Nursery and Landscape Association (MNLA) Foundation
15_Pruning_ppt.doc

2. LANDSCAPE AND TURF MANAGEMENT LESSON 15 - PRUNING

3. Overview Definition of Pruning Reasons for Pruning
When to Prune (timing)
Pruning Tools
Rules of Pruning
Apical Dominance
Pruning Techniques
15_Pruning_ppt.doc

4. Definition of Pruning
A horticultural practice involving the removal of portions of a plant to control growth, form and size, correct structural defects, improve health, vigor and structure, and enhance flowering and fruiting.
The removal of plant parts for a purpose.
Because plant parts are removed, pruning initially decreases the size of a plant, but can revitalize plants and ultimately stimulates new growth.
15_Pruning_ppt.doc

5. I. Reasons to Prune
Young trees are pruned to encourage proper development and natural form and to create a well- spaced, sturdy set of scaffold branches. These branches are the basis for a strong and well-structured crown.
Older trees are pruned to maintain their natural form and vigor; dead, dying, diseased, rubbing/crossing, and broken branches are removed.
15_Pruning_ppt.doc

6. I. Reasons to Prune
To repair damage (damage from storms and other types of mechanical damage).
To direct or control growth; except for mowing grass, controlling size should not be a primary reason for pruning (if extensive and repeated pruning is required to keep a plant from getting too big for a given location, it is the wrong plant and it should be replaced).
15_Pruning_ppt.doc

7. I. Reasons to Prune
To encourage flowering and fruit production and to improve fruit quality.
To create specialized or unique forms (e.g., topiary, espalier, bonsai).
During production, root pruning is used to create compact, well-branched, transplantable root systems.
To remove dead/faded flowers (deadheading).
15_Pruning_ppt.doc

8. I. Reasons to Prune
Topping of older trees to reduce size and wind resistance is never an acceptable practice; the natural form is destroyed and the result is unsightly and increases the potential for internal decay and increased storm damage; topped trees are likely to become hazard trees.
15_Pruning_ppt.doc

9. When to Prune Late Winter (dormant season) Spring Summer Fall
15_Pruning_ppt.doc

10. Prune in Spring
Plants that bloom in early spring on old wood (last season’s growth): (Prune just after flowering)
Amelanchier spp. Serviceberries/Juneberries
Forsythia spp. Forsythias
Lonicera spp. Honeysuckles
Magnolia spp. Magnolias
Prunus spp. Cherries, Plums, Apricots, etc.
Rhododendron spp. Azaleas and Rhododendrons
Ribes spp. Currants, Gooseberries
Spiraea spp. Spring blooming Spireas (white)
Syringa spp. Lilacs
15_Pruning_ppt.doc

11. Prune in Late Winter or Spring
Plants that bloom in late spring/early summer on old wood (last season’s growth): (Prune before growth starts in the spring or just after flowering)
Philadelphus spp. Mockoranges
Potentilla spp. Shrubby Cinquefoil
Rosa spp. Some Shrub Roses
Viburnum spp. Viburnums
Weigela spp. Weigelas
15_Pruning_ppt.doc

12. Prune in Late Winter or Early Spring
Plants that bloom on new wood (current season’s growth): (Prune before growth starts in the spring)
Clematis spp. Clematises
Clethra alnifolia Summer Sweet
Hydrangea spp. Hydrangeas
Rosa spp. Some Shrub Roses
Spiraea spp. Summer Blooming Spireas (pink)
15_Pruning_ppt.doc

13. Prune in Late Winter or Early Spring
Plants that are primarily grown for their foliage: (Prune before growth starts in the spring)
Euonymus spp. Euonymus
Ribes alpinum Alpine Currant
15_Pruning_ppt.doc

14. Prune in Summer
Plants that “bleed” sap if pruned in winter or early spring: (Prune in summer)
Acer spp. Maples
Betula spp. Birches
Gleditsia triacanthos Honeylocust
Juglans spp. Butternuts, Walnuts
Ostrya virginiana Ironwood
Ulmus spp. Elms
15_Pruning_ppt.doc

15. Late Summer/Fall Pruning
In general pruning should be avoided in late summer and fall; pruning at this time of year can sometimes stimulate new growth that may not harden off in time for winter and may be injured by winter temperatures.
Broken branches can be removed at any time during the year including during the fall.
15_Pruning_ppt.doc

16. Prune in Winter
Plants whose susceptibility to diseases can be increased if pruned during the growing season are best pruned during the winter when they are dormant; pruning in late winter is generally best.
Quercus spp. Oaks (to avoid oak wilt)
(especially those in the red oak group)
Cotoneaster, Crataegus, Cotoneasters, Hawthorns,
Malus, Pyrus, and Apples & Crabapples, Pears, and
Sorbus spp. Mountain Ash (to avoid fireblight)
15_Pruning_ppt.doc

17. Pruning Tools Hand Pruners (bypass/scissor type)
Small branches up to about ½”
Lopping Shears (bypass/scissor type)
Branches up to about 1½”
Pole Pruners (often equipped with a bypass pruner and a saw blade)
Hedge Shears
Pruning Saws
Chain Saws
Bypass Type Hand Pruner
15_Pruning_ppt.doc

18. Pruning Techniques
Know the plant (identify the plant and understand its growth habits and natural form) and prune accordingly based on the pruning objectives.
Have a plan – know your pruning objectives and have a reason for every pruning cut; pruning cuts are wounds and shouldn’t be made without good reason; pruning cuts also can’t be undone and have a lasting effect which can be positive or negative.
15_Pruning_ppt.doc

19. Pruning Techniques
Use the proper tool in the correct manner; pruning tools should be clean, sharp (precise cuts heal more quickly than rough cuts) and in good working condition.
Keep pruning cuts (wounds) small by pruning sooner rather than later.
Never leave stubs, but avoid flush cuts.
15_Pruning_ppt.doc

20. Pruning Techniques
Do not cut into the branch collar (but, again, don’t leave stubs).
With a few exceptions, the best time to prune is during the dormant season; late winter/early spring just before growth begins (March/April).
As a general rule, no more than one third of the living crown should be removed each year.
15_Pruning_ppt.doc

21. Apical Dominance
When the terminal (topmost) bud is dominant, the degree of apical dominance determines the form of a plant and varies among species; strong apical dominance results in a conical form while weak apical dominance results in broader forms (upright oval and rounded forms). Vines have very strong apical dominance and relatively weak stems.
Heading back to remove the terminal bud can promote branching and increased density by promoting the growth of axillary (side) buds, but will be less effective for plants that exhibit strong apical dominance.
15_Pruning_ppt.doc

22. Apical Dominance
Terminal Bud
When the terminal (topmost) bud is dominant, the degree of apical dominance determines the form of a plant and varies among species. Strong apical dominance results in a conical form while weak apical dominance results in broader forms (upright oval and rounded forms). Vines have very strong apical dominance and relatively weak stems.
Heading back to remove the terminal bud can promote branching and increased density by promoting the growth of axillary (side) buds, but will be less effective for plants that exhibit strong apical dominance.
15_Pruning_ppt.doc

23. Apical Dominance
15_Pruning_ppt.doc

24. Apical Dominance
15_Pruning_ppt.doc

25. Apical Dominance
15_Pruning_ppt.doc

26. Pruning Techniques
Pinching stems back to increase plant density (herbaceous plants)
Heading back small branches
Removing large branches
Thinning
Gradual renewal
Rejuvenation pruning
Evergreen trees & shrubs
Hedges
Root pruning
Deadheading
15_Pruning_ppt.doc

27. Heading Back Small Branches
Head back to an outward growing bud and cut at a 45º angle just above the bud.
15_Pruning_ppt.doc

28. Heading Back Small Branches
15_Pruning_ppt.doc

29. Heading Back Small Branches
Prune back to an outward growing branch,
not branches growing back into the plant.
15_Pruning_ppt.doc

30. Removing Large Branches
15_Pruning_ppt.doc

31. Removing Large Branches
The ultimate goal, but remove the weight of the branch first to avoid stripping the bark.
15_Pruning_ppt.doc

32. Removing Large Branches
Use three cuts
15_Pruning_ppt.doc

33. Removing Large Branches
Use three cuts
15_Pruning_ppt.doc

34. Removing Large Branches
Use three cuts
15_Pruning_ppt.doc

35. Removing Large Branches
Branch Collar
Do not cut into the branch collar
Use three cuts
15_Pruning_ppt.doc

36. Deciduous Shrubs
Selectively heading back branches to open up the crown of the plant.
15_Pruning_ppt.doc

37. Deciduous Shrubs
Selectively heading back branches to open up the crown of the plant.
15_Pruning_ppt.doc

38. Deciduous Shrubs
Multi-Stemmed Shrubs – Removing up to 1/3 of the stems to the ground to stimulate new growth from the base of the plant. Maintains natural form, keeps plants shorter, maintains flowering and fruiting.
15_Pruning_ppt.doc

39. Deciduous Shrubs
Multi-Stemmed Shrubs – Removing up to 1/3 of the stems to the ground to stimulate new growth from the base of the plant. Maintains natural form, keeps plants shorter, maintains flowering and fruiting.
15_Pruning_ppt.doc

40. Deciduous Shrubs
Multi-Stemmed Shrubs – Removing up to 1/3 of the stems to the ground to stimulate new growth from the base of the plant, maintains natural form. Keeps plants shorter, maintains flowering and fruiting.
Cutting the entire plant to the ground is called rejuvenation and can be used on vigorous plants that sucker from the base. Flowering and fruiting will not occur for several years.
15_Pruning_ppt.doc

41. Evergreen Trees and Shrubs
Candle Growth in Early Spring
Yew
Pines
Spruce, Fir, Hemlock, Yew, Arborvitae, Juniper, & Broadleaf Evergreens
15_Pruning_ppt.doc

42. Hedges
Plants planted in rows for screening or to define landscape spaces (hedges) may be maintained in their natural form or may be sheared for a formal effect.
Shearing is higher maintenance.
When sheared, being wider at the base allows for better light exposure and avoids bare stems as a result of shading.
15_Pruning_ppt.doc

43. Review Definition of Pruning Reasons for Pruning
When to Prune (timing)
Pruning Tools
Rules of Pruning
Apical Dominance
Pruning Techniques
15_Pruning_ppt.doc

44. Definition of Pruning
A horticultural practice involving the removal of portions of a plant to control growth, form and size, correct structural defects, improve health, vigor and structure, and enhance flowering and fruiting.
15_Pruning_ppt.doc

45. Reasons for Pruning
To encourage proper development, natural form, and vigor.
To repair damage.
To direct or control growth.
To encourage flowering and fruit production and to improve fruit quality.
To create specialized or unique forms (e.g., topiary, espalier, bonsai).
To create compact, well-branched, transplantable root systems.
To remove dead/faded flowers (deadheading).
15_Pruning_ppt.doc

46. When to Prune (timing) Late winter (dormant season) Spring Summer Fall
Most pruning is performed in late winter and early spring.
15_Pruning_ppt.doc

47. When to Prune
Late winter/early spring (before new growth begins) – shrubs that bloom on current season’s growth; shrubs grown primarily for their foliage; most trees.
Spring (just after flowering) – shrubs that bloom on last season’s growth.
Summer – limited, minor pruning (e.g., removing dead wood and broken branches); trees that “bleed” sap in early spring if pruned in winter.
Fall – limited, minor pruning (e.g., removing dead and broken branches).
15_Pruning_ppt.doc

48. Pruning Tools Hand Pruners Lopping Shears Pole Pruners Hedge Shears
Pruning Saws
Chain Saws
15_Pruning_ppt.doc

49. Rules of Pruning
Know the plant (identify the plant and understand its growth habits and natural form) and prune accordingly based on the pruning objectives.
Have a plan – know your pruning objectives and have a reason for every pruning cut. Pruning cuts are wounds and shouldn’t be made without good reason; pruning cuts can’t be undone and have a lasting effect which can be positive or negative.
Use the proper tool in the correct manner; pruning tools should be clean, sharp (precise cuts heal more quickly than rough cuts), and in good working condition.
Keep pruning cuts (wounds); prune sooner rather than later.
Never leave stubs, but avoid flush cuts.
Do not cut into the branch collar (but, again, don’t leave stubs).
With a few exceptions, the best time to prune is during the dormant season; late winter/early spring just before growth begins (March/April).
As a general rule, no more than one third of the living crown should be removed each year.
15_Pruning_ppt.doc

50. Pruning Techniques
Pinching – pinching stems back to increase plant density (herbaceous plants)
Removing Side Branches – cut just outside the branch collar, not flush with the trunk
Thinning – removing individual branches to make plants more open (trees and shrubs)
Heading Back – shortening branches by cutting back to an outward pointing bud (mainly shrubs)
Gradual Renewal/Rejuvenation – removing entire stems near the ground to renew from the base (mainly shrubs)
Hedges – choose between natural form or sheared; shearing is higher maintenance
Root Pruning
Deadheading
15_Pruning_ppt.doc

51. 15_Pruning_ppt.doc

52. Connect with horticulture and landscaping resources.
Thank you for using the Pathways through Horticulture Curriculum, provided to Minnesota teachers free-of-charge, courtesy of the Minnesota Nursery & Landscape Association and the MNLA Foundation.
For more information or to inquire about other resources offered by the MNLA Foundation, please contact:
MNLA Foundation
Office:
Connect with horticulture and landscaping resources.
Your resource for careers in the green industry.  
These lessons were obtained through a purchase agreement between the Minnesota Nursery and Landscape Association (MNLA) and the Pennsylvania Landscape and Nursery Association (PLNA) and have been modified by the MNLA. The Pennsylvania Landscape and Nursery Association retains all original ownership rights and all copyrights. © 2005, Pennsylvania Landscape and Nursery Association. All Rights Reserved.